This invention is generally concerned with wall erection systems and methods, and is specifically concerned with a rapidly erectable, removable, reusable and raisable post and panel-type acoustical wall system.
Acoustical wall systems for obstructing highway noises from residential areas are known in the prior art. Such wall systems generally take three different forms, including self-supporting walls, monolithic post and panel precast walls, and separate steel/concrete or wood post and panel precast walls. When viewed from above, self-supporting wall systems have an undulating profile which resembles a square or trapezoidal wave function which makes them self-supporting without the need for deep underground foundations. They are used where a flat and wide right-of-way is available on either side of the noise-generating highway, and where the ground provides good foundational support. Unfortunately, the larger amount of panel surface caused by the square or trapezoidal-wave profile of these walls necessitates 10% to 30% more structural and sound obstructive materials for their construction, which in turn causes them to be relatively expensive. Additionally, self-supporting wall systems are not compatible with certain desirable architectural wall finishes, and are difficult to install in terrain having significant relief. While self-supporting walls can be removed and reused, such removal and reuse is labor and equipment intensive. Finally, because of the section required to develop the weight required to be self-supporting, the economical height to which the wall can be raised is limited.
Monolithic precast wall systems employ single-monolithic panels supported by concrete support columns integrally cast into the side edges of the panels. They are erected by tongue and groove connections between adjacent panels, and connections between the bases of the columns and a structural foundation is normally welded or bolted. While monolithic precast walls advantageously employ fewer amounts of wall panel materials than self-supporting walls, they are permanent structures which would be removable only with great difficulty with the help of large equipment requiring large amounts of working space. Additionally, these walls are not raisable or otherwise height-adjustable. Moreover, because the alignment of the joints between adjacent panels is dependent upon the grade of the specific terrain that the wall is initially erected on, it is difficult to re-use the same panels in a location having a different grade.
Post and panel acoustical wails employ panels that are slidably mounted between and supported by structurally independent support posts. The support posts are typically steel or concrete columns having opposing pairs of flanges which slidably receive the side edges of wall panels upon the raising of a panel by a crane above two adjacent support posts, and the subsequent lowering of the panel between the posts after the side edges are aligned between the flange pairs. Either a single panel or a stack of panels may be mounted between two adjacent posts. While post and panel walls have certain installation advantages over monolithic precast walls, they also have their disadvantages. One major disadvantage stems from the necessity of having to leave some amount of slack in the distance between the flanges of the support posts and the thickness of the side edges so that the panels may be quickly aligned between the flanges of the beams prior to slidably lowering them between two flange pairs of adjacent posts. As a result of this slack, the front side edges of the panels cannot snugly engage the front flanges of their respective support posts, which if not corrected will create substantial acoustical leaks in the resulting wall, and poor structural alignment of the panels.
In the past, this slack has been eliminated by the installation of steel angle members between the back flanges of the support posts and the back side edges of the panels to take up the unwanted slack in combination with the application of caulking between the panels and the posts. However, the installation of such steel angles has proven to be an expensive and time consuming step in the assembly of such wall systems, as it requires the drilling of a specific pattern of holes through the flanges of the I-beams forming the support posts, the regalvanization of the I-beams, as well as the tedious installation of several nuts and bolts for every angle in such a way that they continuously apply pressure to the back side edges of the panel. The materials cost is also substantial, not only with respect to the steel angles themselves, but the nuts and bolts necessary to mount them as well. Moreover, the use of such steel angle members sometimes fails to permanently remove unwanted slack between the front side edges of the panels and the flanges of the posts because of the constant vibration that such wall systems are subjected to due to their proximity to a heavy flow of road traffic. Vandals have occasionally been known to remove the nuts and bolts that secure the angle members in their place, which of course necessitates their replacement with its attendant expenses. Both the caulking of the panels and the posts and the installation of the numerous nuts and bolts used to mount the angle members substantially slows down both the raising and the disassembly of the wall system (should removal of the wall become desirable). Additionally, the custom pattern of bolt holes that must be drilled or molded in the flanges of each of the I-beams forming the posts makes it difficult, if not impossible, to reuse the same post structures should it become desirable to rebuild the wall system at a different location. The raising would require substantial reengineering of the post which has holes punched in the structural flanges.
Clearly, there is a need for an improved post and panel type acoustical wall system which overcomes all of the aforementioned disadvantages associated with the angle members used in prior art wall systems, and which provides an alternate means for removing unwanted slack between the back side edges of the panels and the flanges of the posts which does not impede the raising, disassembly or removability of the wall system. Ideally, such an alternative slack-removing means would not necessitate the drilling of a custom pattern of holes in the I-beams forming the posts so that the posts could be easily reused to build another wall system should it ever become desirable to remove or relocate the original wall system. The slack removing means should also be durable, inexpensive, versatile, and not easily prone to destruction by either weather conditions or vandalism. The resulting wall systems should also be rapidly erectable, removable, easily reusable, and raisable beyond the height of the originally-used posts to accommodate changes in the acoustical conditions surrounding the highway (which might occur, for example, if the highway were widened).